Subarachnoid block with hyperbaric lignocaine. A comparison with hyperbaric bupivacaine.

A double-blind study was carried out in 20 patients to compare 5% hyperbaric lignocaine and 0.5% hyperbaric bupivacaine for subarachnoid block. The injections were made in the lateral position and the patients turned supine immediately. The onset, extent and duration of sensory and motor blockade, the quality of anaesthesia, cardiovascular effects and the frequency of side effects were studied. Cephalad spread of analgesia was high (T4-5) with both solutions. Bupivacaine produced a longer duration of action in the lumbar and sacral segments but the duration in the thoracic segments was similar. There was a considerable degree of hypotension in both groups but this responded readily to ephedrine. Hyperbaric lignocaine is an alternative to hyperbaric bupivacaine and its shorter duration of action in the lumbar and sacral segments is advantageous when a fast recovery is desirable.